CA2140303C - Adhesive for methacrylate plastics - Google Patents

Adhesive for methacrylate plastics Download PDF

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Publication number
CA2140303C
CA2140303C CA002140303A CA2140303A CA2140303C CA 2140303 C CA2140303 C CA 2140303C CA 002140303 A CA002140303 A CA 002140303A CA 2140303 A CA2140303 A CA 2140303A CA 2140303 C CA2140303 C CA 2140303C
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CA
Canada
Prior art keywords
adhesive
plastics
bonding
plastic
bonded
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Fee Related
Application number
CA002140303A
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French (fr)
Other versions
CA2140303A1 (en
Inventor
Michael Blumenschein
Michael Mueller
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Roehm GmbH Darmstadt
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Roehm GmbH Darmstadt
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Roehm GmbH Darmstadt filed Critical Roehm GmbH Darmstadt
Publication of CA2140303A1 publication Critical patent/CA2140303A1/en
Application granted granted Critical
Publication of CA2140303C publication Critical patent/CA2140303C/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

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Classifications

    • CCHEMISTRY; METALLURGY
    • C08ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08JWORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J5/00Manufacture of articles or shaped materials containing macromolecular substances
    • C08J5/12Bonding of a preformed macromolecular material to the same or other solid material such as metal, glass, leather, e.g. using adhesives
    • C08J5/122Bonding of a preformed macromolecular material to the same or other solid material such as metal, glass, leather, e.g. using adhesives using low molecular chemically inert solvents, swelling or softening agents
    • CCHEMISTRY; METALLURGY
    • C08ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08JWORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J5/00Manufacture of articles or shaped materials containing macromolecular substances
    • C08J5/12Bonding of a preformed macromolecular material to the same or other solid material such as metal, glass, leather, e.g. using adhesives
    • C08J5/124Bonding of a preformed macromolecular material to the same or other solid material such as metal, glass, leather, e.g. using adhesives using adhesives based on a macromolecular component
    • C08J5/125Adhesives in organic diluents
    • CCHEMISTRY; METALLURGY
    • C08ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08JWORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J2333/00Characterised by the use of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides, or nitriles thereof; Derivatives of such polymers
    • C08J2333/04Characterised by the use of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides, or nitriles thereof; Derivatives of such polymers esters
    • C08J2333/06Characterised by the use of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides, or nitriles thereof; Derivatives of such polymers esters of esters containing only carbon, hydrogen, and oxygen, the oxygen atom being present only as part of the carboxyl radical
    • C08J2333/10Homopolymers or copolymers of methacrylic acid esters
    • C08J2333/12Homopolymers or copolymers of methyl methacrylate

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Health & Medical Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Organic Chemistry (AREA)
  • Adhesives Or Adhesive Processes (AREA)
  • Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)
  • Compositions Of Macromolecular Compounds (AREA)
  • Manufacture Of Macromolecular Shaped Articles (AREA)

Abstract

Methacrylic plastics are bonded to each other and other plastics by applying an adhesive of a low molecular weight alkyl formate or a volatile adhesive mixture or adhesive varnish containing a low molecular weight alkyl formate to at least one bonding surface of plastics to be bonded to each other, at least one of the plastics being a methacrylate plastic, and bonding plastic surfaces to each other.

Description

2~.4~'~~~

TITLE OF THE INVENTION
ADHESIVE FOR METHACRYLATE PLASTICS
BACKGROUND OF THE INVENTION
Field of the Invention:
The present invention relates to adhesives for methacrylate plastics in the form of volatile organic fluids or in the form of adhesive varnishes consisting of a solution of a polymer in such a fluid.
Description of the Background' EP-B 867 application describes an adhesive for methacrylate plastics which contains nitromethane or nitroethane as a solvent. Optimum adhesive properties are found when mixtures of nitromethane and dichloromethane are employed.
Task and Solution Dichloromethane and other chlorinated hydrocarbons are considered toxic and carcinogenic. For this reason, there is a need for an adhesive for methacrylate plastics that does not contain chlorinated hydrocarbons, but has properties comparable to those of nitromethane-dichloromethane mixtures.
Requirements include short superficial dissolving times and low stress corrosion cracking, as well as low toxicity.
SUMMARY OF THE INVENTION
Accordingly, one object of the present invention is to provide an adhesive material for methacrylate plastics which achieves bonding of such plastics of improved strength, which 2~4Q303 adhesive does not contain a chlorinated hydrocarbon component.
Briefly, this object and other objects of the present invention as hereinafter will become more readily apparent can be attained in a method of bonding methacrylate plastic to each other and other plastic materials by applying adhesive of a low molecular weight alkyl formate or a volatile adhesive mixture or adhesive varnish containing a low molecular weight alkyl formate to at least one bonding surface of plastics to be bonded to each other, at least one of said plastics being a methacrylate plastic, and bonding the plastic surfaces to each other.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention is directed to a low-molecular weight alkyl formate as an adhesive or as an additive to volatile adhesive mixtures, or as an additive to adhesive varnishes for bonding parts of methacrylate plastics to each other or with other plastics. A preferred aspect of the invention is the use of a mixture of at least 15 wt.% of a low-molecular weight alkyl formate and up to 85 wt. % of other volatile organic fluids free of chlorinated hydrocarbons and having a boiling point not exceeding 200°C, particularly nitromethane and/or nitroethane.~
During the superficial dissolving process, the swelling plastic surface exerts a significant swelling pressure on the material layer beneath it, possibly resulting in tearing. The adhesive of the present invention has the surprising effect that swelling, softening and dissolving processes interact in such a way that tearing is largely suppressed, and tears that do form are largely closed again due to the effect of the adhesive. Although not all of the advantageous properties of the known nitromethane-dichloromethane mixtures are obtained, the adhesives according to the invention, because of their complete absence of chlorinated hydrocarbons and an improved strength of the adhesive bonds, represent an important improvement in the field of methacrylate plastics bonding.
Volatile Adhesives l0 A volatile adhesive of the present invention is one which superficially dissolves plastic surfaces and brings about adhesion, while the adhesive completely evaporates again.
These solvents are suitable for bonding parts with an exact fit relative to each other. It is advantageous that they have boiling points from 30 to 150°C (under normal pressure).
Suitable volatile solvents include alkyl formates such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, n-amyl, isoamyl, and n-hexyl formates. Because of their high volatility, methyl fornaate and ethyl formate are particularly preferred.
Mixtures of at least 15 wt. % of a low-molecular alkyl formate and up to 85 wt. % of other volatile organic fluids free of chlorinated hydrocarbons having a boiling point not exceeding 200°C have various advantages compared to the alkyl formates by themselves. While methyl and ethyl formate alone may result in tearing, particularly when bonding plastic parts with internal tensions, this risk is much lower when using 21~03n~
mixtures with nitromethane and nitroethane. Mixtures of 25 to 75 wt. % methyl formate and/or ethyl formate and 75 to 25 wt.
% nitromethane and/or nitroethane are preferred. The addition of other solvents, such as ketones or esters, e.g. ethyl acetate, are also within the scope of the invention.
By adding 0.5 to 10 wt.% of alcohols having boiling points between 70 and 280°C, improvements in the quality of the adhesive joints can be achieved. Because of lower volatility, they are temporarily concentrated during the drying of the adhesion joint at their surface. This prevents flaws in the surface that may result from premature skin formation or from condensation of water from humid ambient air because of cooling caused by evaporation. An addition of n-butanol, e.g. prevents wrinkling; the addition of phenoxyethanol prevents the clouding of the adhesive joint in the case of high air humidity.
Adhesive Varnishes Adhesive varnishes are adhesives with a polymer content which remains in the adhesive joint after the evaporation of 20. the volatile components and produces the bond between the bonded parts. Adhesive varnishes are advantageous if the parts to be bonded cannot be form-fitted together, and if during the bonding, distances of e.g. 0. 1 to 1 mm must be bridged.
Like any adhesive resin, the dissolved polymer must have a sufficient adhesiveness to the material of the parts to be bonded, and also a sufficient internal strength. These 2~~o~a..
conditions are best fulfilled if the dissolved polymer itself is a methacrylate plastic, e.g., polymethylmethacrylate.
Thermoplastic polymers are preferred. Other suitable adhesive resins are polyvinyl acetate, polyvinyl ether, or cellulose 5 acetobutyrate. The polymer content has an upward limit based on the viscosity of the solution. The solution viscosity at 20°C generally should not exceed 10,000 mPa s. It is advantageous to use approximately 3 to 30 wt. % of a polymer which results in a viscosity~of the solution ranging from 500 to 2,000- mPa s.
Bonding of Methacrylate Plastics The adhesives to be used according to the invention primarily serve to bond parts of methacrylate plastics with each other or with parts of other plastics such as polyvinyl chloride, polystyrene, butadiene-styrene plastics;- ABS
plastics, or cellulose esters (CAB). In order to bond methacrylate plastics to other materials such as wood, paper, cardboard, leather, metal, ceramic material, glass, porcelain, the adhesive varnishes of the invention are preferably used.
A suitable methacrylate plastic is in particular acrylic glass. Examples are poured, extruded, or injection-molded polymethylmethacrylate or copolymers of the methylmethacrylate with no more than 10 wt. % of other ethylene-unsaturated radically polymerizable monomers, particularly low-molecular alkyl acrylates. The methacrylate plastics also include methylmethacrylate-acrylonitrile copolymers, methylmethacrylate-styrene-malefic anhydride copolymers, 214~~~~
shock-resistant modified polymethylmethacrylate, and the like.
To bond with volatile adhesives, the closely fitting bonding surfaces are wetted with the adhesive and joined in the desired position. The adhesive also can be applied to the edge of the contact surface, so that it is drawn by itself into the gap between the bonding parts because of capillary force. When using adhesive varnishes, it is sufficient if one of the plastic surfaces to be bonded is coated with a thickness sufficient to fill the joint, and to join the parts 1Q together.
The superficial dissolving time, during which the parts to be bonded are easily moved relative to each other, usually lasts approximately 30 to 90 seconds. After this, a sufficient stability is achieved for holding the parts to be bonded in the desired position even without support. The adhesive joint is then left to stabilize, preferably under a slight pressure, because of evaporation of the volatile adhesive components. After a drying time of 1 to 4 hours, a high adhesion strength is obtained. It clearly increases during the course of 1 to 2 weeks, or preferably by tempering for 2 to 6 hours at 60 to 90°C.
Having generally described this invention, a further understanding can be obtained byvreference to certain specific examples which are provided herein for purposes of illustration only and are not intended to be limiting unless otherwise specified.
Determination of Adhesive Strength The following table contains combined tension and shear ~140~~3 ..
resistance values measured on bonded parts of extruded and poured acrylic glass with the following adhesives of the invention:
A) Volatile adhesive (wt. %), viscosity 500-700 mPa s:
44% ethyl formate, 44% nitroethane, 4 %
phenoxyethanol, 3 % n-butanol, 5 % acetic ester;
B) Adhesive varnish (wt.%), viscosity 750- 1,000 mPa s:
39 % ethyl formate, 39 % nitroethane, 4 %
phenoxyethanol, 3 % n-butanol, 5 % acetic ester, 10%
polymethylmethacrylate.
These examples of the invention are compared with known adhesives C and D with the compositions:
C) Volatile adhesive (wt. %): 52 % dichloromethane, 40 % nitromethane, 5 % phenoxyethanol, 3% ethanol 15 D) Adhesive varnish (wt.%): 44 % dichloromethane, 36 %
nitromethane, 7 % phenoxyethanol, 3% ethanol, 10%
polymethylmethacrylate.
The combined tension and shear resistance is measured by 20 subjecting a 2 cm2 large adhesive area to tensile stress in the direction of the adhesive area. The first measurement is taken after drying at room temperature for 5 days, the second measurement after tempering over 5 hours at 80°C.
Bonded plastics Comb. shear resistance in mPa tension and 25 -adhesive after 5 days after tempering Cast -pe~rree~- acrylic glass (PLEXIGLAS GS) Nov. 24 - volatile adhesive A 31.3 42.3 , - adhesive varnish B 31.0 46.0 ~~"

-0 C 30.3 33.9 volatile adhesive - adhesive varnish D 27.6 31.7 r Extruded acrylic glass (PLEXIGLAS XT) - volatile adhesive A 39.3 51.6 Nov. 24 - adhesive varnish B 40.1 54.2 , 35 - volatile adhesive C 37.9 43.2 -dh i a D 34.9 43.6 es ve varnish ~~~o~o~
Bonding Under Bending Stress Two strips measuring 85 x 10 x 2 mm of extruded acrylic glass were placed on top of each other with their surfaces and connected at the ends with lead adhesive tape. The strips were then elastically spread apart by way of spacers placed between them in the center, resulting in a uniform bending radius of 500-600 mm, corresponding to a bending stress of 6 Mpa. The strips subject to bending stress were glued with their edges onto a plane plate of extruded acrylic glass.
After drying, the tearing and bubbling in the adhesive area and on the convex outside surfaces were evaluated.
For bonding, the volatile adhesive A and the adhesive varnish B according to the invention, and for control purposes the liquid adhesive C and adhesive varnish D based on 1~ dichloromethane/nitromethane were used. Findings:
A: no tears in bonded area, many fine tears along edge, few bubbles B: no tears in bonded area, many fine tears in outer bonding edge, _C: no tears in bonded area, very fine tears, in part closed by dissolving, on edge D: no tears, many bubbles.
Having now fully described the invention, it will be apparent to one of ordinary skill in the art that many changes and modifications can be made thereto without departing from the spirit or scope of the invention as set forth herein.

Claims (8)

1. A method of bonding methacrylate plastics to each other and other plastic materials, comprising:
applying an adhesive of a low molecular weight alkyl formate or a volatile adhesive mixture or adhesive varnish containing a low molecular weight alkyl formate to at least one bonding surface of plastics to be bonded to each other, at least one of said plastics being a methacrylate plastic; and bonding the plastic surfaces to each other.
2. The method of Claim 1, wherein said adhesive is or contains a mixture of at least 15 wt% of a low molecular weight alkyl formate and up to 85 wt % of other volatile organic fluids free of chlorinated hydrocarbons and having a boiling point not exceeding 200°C.
3. The method of Claim 2, wherein said alkyl formate is methyl formate, ethyl formate or combinations thereof.
4. The method of Claim 2 or 3, wherein said other volatile organic fluid is nitromethane, nitroethane or combinations thereof.
5. The method of Claim 2 or 3, wherein said adhesive mixture or varnish contains 0.5 to 10 wt% of an alcohol having a boiling point between 70° and 280°C.
6. The method of Claim 2, wherein the adhesive material contains dissolved polymer and has a solution viscosity which does not exceed 10,000 mPa s at 20°C.
7. The method of Claim 1, wherein a plastic being bonded is acrylic glass.
8. The method of Claim 7, wherein said acrylic glass is extruded acrylic glass.
CA002140303A 1994-01-17 1995-01-16 Adhesive for methacrylate plastics Expired - Fee Related CA2140303C (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE4401160A DE4401160A1 (en) 1994-01-17 1994-01-17 Adhesive for methacrylic ester plastics
DEP4401160.1 1994-01-17

Publications (2)

Publication Number Publication Date
CA2140303A1 CA2140303A1 (en) 1995-07-18
CA2140303C true CA2140303C (en) 2004-03-30

Family

ID=6508066

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Application Number Title Priority Date Filing Date
CA002140303A Expired - Fee Related CA2140303C (en) 1994-01-17 1995-01-16 Adhesive for methacrylate plastics

Country Status (6)

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EP (1) EP0663419B1 (en)
AT (1) ATE159540T1 (en)
CA (1) CA2140303C (en)
DE (2) DE4401160A1 (en)
DK (1) DK0663419T3 (en)
ES (1) ES2109739T3 (en)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102011088147A1 (en) 2011-12-09 2013-06-13 Evonik Industries Ag Composite body comprising a composite material

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB567098A (en) * 1942-02-03 1945-01-29 Ici Ltd Improvements in or relating to the cementing of moulded methyl methacrylate resins
CH303673A (en) * 1952-04-16 1954-12-15 Lonza Ag Process for bonding plastics.
EP0000867B1 (en) * 1977-08-18 1981-04-15 Röhm Gmbh Adhesives for methacrylic ester plastics
US4687798A (en) * 1986-01-27 1987-08-18 King Lloyd H Sr Solvent cement

Also Published As

Publication number Publication date
DK0663419T3 (en) 1998-02-23
ES2109739T3 (en) 1998-01-16
CA2140303A1 (en) 1995-07-18
EP0663419B1 (en) 1997-10-22
DE4401160A1 (en) 1995-07-20
DE59500814D1 (en) 1997-11-27
EP0663419A1 (en) 1995-07-19
ATE159540T1 (en) 1997-11-15

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Effective date: 20150116